High and low temperature resistant toughened brown silk triangular belt and preparation method thereof

Abstract

The application belongs to the technical field of V-belts, and particularly relates to a high and low temperature resistant toughened brown silk V-belt and a preparation method thereof. The V-belt comprises a strength layer, an upper portion of the strength layer is provided with a tension layer, a lower portion of the strength layer is provided with a compression layer, and the outer sides of the tension layer and the compression layer are wrapped with a wrapping layer. The pretreated toughened brown silk is pulled through the molten tension layer glue to form a buffer cord, the buffer cord is wound to form a pre-use layer through a rotating roller, the compression layer glue is bonded to the lower portion of the pre-use layer to form a base layer, the base layer is wrapped through the wrapping layer, and the prepared V-belt is obtained after vulcanization, and the V-belt has good mechanical properties and thermal stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of V-belt, in particular to a high and low temperature resistant toughened brown silk V-belt and a preparation method thereof. BACKGROUND

[0002] V-belt is a kind of conveyor belt, and the belt transmission is one of important transmission forms of mechanical transmission, which includes a strength layer, a stretching layer, a compression layer and a wrapping layer, wherein the strength layer is the skeleton of the V-belt and mainly bears the tensile stress generated in the running process of the V-belt, and is the main stress part in the transmission process of the V-belt, the stretching layer is usually composed of a rubber material with high elasticity and excellent stretching performance, and bears the tensile stress in the running bending process, the compression layer is usually composed of a rubber material with excellent bending fatigue resistance, and bears the compression stress generated in the running bending process of the V-belt, and maintains the rigidity and elasticity of the V-belt, and the wrapping layer usually has excellent stretching and friction properties, and can connect each part into a whole to protect other parts from wear and corrosion; with the development of industry and the requirements of precision, light weight and functionality of mechanical equipment, the V-belt is continuously developed in the direction of high precision, high speed, high power, high efficiency, high reliability, long service life, low noise and low vibration, and its application range is wider and wider, and the quality requirements of ordinary V-belt products are higher and higher, especially the fatigue life requirements of the V-belt are greatly improved.

[0003] A high tensile strength and high weather resistance V-belt and a preparation method thereof are disclosed in Chinese patent No. 201810024910.1, which comprises a strength layer, a buffer rubber layer wrapped outside the strength layer, a compression rubber layer arranged at the lower end surface of the buffer rubber layer, and a wrapping layer wrapped outside the buffer rubber layer and the compression rubber layer, the compatibility and mixing uniformity of the vulcanizing agent, chloroprene rubber and butadiene rubber are effectively improved by adding sodium succinate sulfonate during the preparation of the compression layer raw material, the addition of zinc oxide makes the compression rubber layer have good corrosion resistance, tear resistance and elasticity, and the introduction of sodium pyrophosphate improves the force between chloroprene rubber, butadiene rubber and vulcanizing agent, so that the prepared V-belt has good elasticity, weather resistance and tensile strength.

[0004] A high-performance triangular belt and a preparation method thereof are disclosed in Chinese Patent No. 201910040828.2. The triangular belt comprises a strong layer, a stretching layer arranged on the upper part of the strong layer, a compression layer arranged on the lower part of the strong layer, and a wrapping layer wrapped on the outer sides of the stretching layer and the compression layer. The strong layer is a surface-modified tempered brown silk. The stretching layer is made of chloroprene rubber, natural rubber, polyurethane resin, talcum powder, aromatic oil, and sodium tripolyphosphate. The compression layer is made of natural rubber, styrene-butadiene rubber, chloroprene rubber, white carbon black, cellulose nanowhisker, tin oxide, vulcanizing machine, compatibilizer, and modified alkali lignin. The surface of the tempered brown silk is treated to leave micropores and transport structures, which are integrated with the bottom glue material to effectively improve the adhesion strength between the tempered brown silk and the bottom glue, and significantly improve the overall triangular rubber.

[0005] However, in the above improvement process, the added raw materials are usually directly mixed, which can easily cause uneven mixing and affect the overall performance of the prepared product. SUMMARY

[0006] To solve the above problems, the present application provides a high and low temperature resistant tempered brown silk triangular belt and a preparation method thereof. The triangular belt comprises a strong layer, a stretching layer, a compression layer, and a wrapping layer. The strong layer is a pretreated tempered brown silk. The stretching layer is prepared from natural rubber, styrene-butadiene rubber, modified polyimide, zinc oxide, stearic acid, aromatic oil, and sodium tripolyphosphate. The compression layer is prepared from natural rubber, cis-butadiene rubber, chloroprene rubber, zinc oxide, aromatic oil, vulcanizing agent, and sodium succinate sulfonate. The pretreated tempered brown silk is pulled through the molten stretching layer compound to form a buffer cord. The cord is wound by a rotating roller to form a pre-use layer. The compression layer compound is bonded to the lower part of the pre-use layer to form a base layer. The base layer is wrapped by the wrapping layer. After vulcanization, the triangular belt prepared by the present application has good mechanical properties and thermal stability.

[0007] The technical solutions provided by the present application are as follows:

[0008] A high and low temperature resistant tempered brown silk triangular belt comprises a strong layer, a stretching layer arranged on the upper part of the strong layer, a compression layer arranged on the lower part of the strong layer, and a wrapping layer wrapped on the outer sides of the stretching layer and the compression layer.

[0009] The strong layer is a pretreated tempered brown silk.

[0010] The stretching layer comprises the following raw materials in parts by weight: natural rubber 25-35 parts, styrene-butadiene rubber 35-55 parts, modified polyimide 15-25 parts, zinc oxide 3-8 parts, stearic acid 2-6 parts, aromatic oil 5-12 parts, and sodium tripolyphosphate 2-8 parts. Preferably, the natural rubber is 32 parts, the styrene-butadiene rubber is 45 parts, the modified polyimide is 22 parts, the zinc oxide is 5 parts, the stearic acid is 4 parts, the aromatic oil is 7 parts, and the sodium tripolyphosphate is 6 parts.

[0011] The compression layer comprises the following raw materials by weight: natural rubber 20-30 parts, butadiene rubber 45-60 parts, chlorobutyl rubber 8-12 parts, zinc oxide 3-9 parts, aromatic oil 8-12 parts, vulcanizing agent 8-12 parts, sodium succinate sulfonate 3-5 parts; preferably natural rubber 24 parts, butadiene rubber 54 parts, chlorobutyl rubber 10 parts, zinc oxide 5 parts, aromatic oil 10 parts, vulcanizing agent 9 parts, sodium succinate sulfonate 4 parts;

[0012] The preparation process of the modified polyimide is as follows: N,N-dimethylacetamide is used as a solvent, modified carborane is added, 4,4'-diamino diphenyl ether is added after stirring, 3,3',4,4'-biphenyl tetracarboxylic dianhydride and pyromellitic dianhydride are added under ice bath conditions, a viscous mixture is obtained after 4-6h of reaction, preferably 5h of reaction, dimethylbenzene is added and stirred uniformly, triethylamine is added dropwise, the temperature is increased to 145-155℃ by heating, water is refluxed out for 3-5h, preferably the temperature is increased to 150℃ by heating, water is refluxed out for 4h, the temperature is decreased for filtration to obtain a powdery substance, the powdery substance is washed in acetone, filtered and dried, the drying condition is 75-85℃ in a vacuum drying oven for 4-6h, preferably 80℃ in a vacuum drying oven for 5h, then the temperature is increased according to the temperature increasing degree, the temperature increasing program is: 1h at 100℃ and 150℃ respectively, 2h at 200℃ and 250℃ respectively, and the modified polyimide is obtained after cooling to room temperature.

[0013] Further, the preparation process of the modified carborane is as follows:

[0014] S1, under an inert atmosphere, toluene and decaborane are added to a reactor and stirring is started, then acetonitrile is added, heated and refluxed for 2-5h, preferably 3h, 1,2-bis(4-methoxyphenyl)acetylene is added after cooling to room temperature, heated and refluxed for 12-18h, preferably 16h, and the solvent is removed under reduced pressure after cooling to obtain a white solid;

[0015] S2, under an inert atmosphere, the white solid obtained in step S1 is added to a light-proof reactor with anhydrous dichloromethane and cooled in ice water, boron tribromide is slowly added, reacted for 1-2h, preferably 2h, the temperature is increased to room temperature for stirring reaction for 18-24h, preferably 20h, and a white solid powder is obtained;

[0016] S3. Under an inert atmosphere, the white solid powder obtained in step S2, 4-(trifluoromethyl)benzyl chloride, and benzyltriethylammonium chloride are mixed and the temperature is raised to react for 2-4 hours, preferably 3 hours. Then, sodium hydroxide aqueous solution is added dropwise. After the addition is completed, the reaction is continued for 1-2 hours and then stopped, preferably 2 hours. The mixture is naturally cooled to room temperature and filtered. The filtrate is washed with water 3-5 times and then anhydrous sodium sulfate is added and allowed to stand overnight, preferably 4 times. The mixture is filtered and evaporated to obtain a viscous liquid. After drying, the modified carborane is obtained. The drying conditions are drying in a vacuum drying oven at 85-100℃ for 16-24 hours, preferably drying in a vacuum drying oven at 95℃ for 20 hours.

[0017] Furthermore, the pretreatment process for tempered palm fibers is as follows:

[0018] A1. Dibutyl phthalate, diphenyl dimethylamine, triethylenetetramine, liquid nitrile rubber, and bisphenol F epoxy resin are mixed and stirred evenly at 55-65°C, preferably 60°C. The temperature is then raised to 70-85°C and reacted for 2-4 hours to obtain a viscous liquid, preferably the temperature is raised to 80°C and reacted for 3 hours.

[0019] A2. Place the tempered brown filaments in the viscous liquid obtained in step A1, and after the tempered brown filaments are fully coated with the liquid, place them in a heating container and treat them at 180-220°C for 40-60 minutes, preferably at 200°C for 45 minutes, to obtain pretreated tempered brown filaments.

[0020] Further, the vulcanizing agent is a mixture of N,N-dicyclohexyl-2-benzothiazole sulfenamide and tetrabenzylthiuram disulfide in a mass ratio of 1:1.

[0021] Furthermore, the inert atmosphere is nitrogen or argon, preferably nitrogen.

[0022] This invention also provides a method for preparing a high and low temperature resistant tempered coir filament V-belt, comprising the following steps:

[0023] B1. First, plasticize natural rubber, styrene-butadiene rubber, and modified polyimide for 80-110 seconds, then add zinc oxide, stearic acid, aromatic oil, and sodium tripolyphosphate and continue mixing for 180-220 seconds. Then, calender the mixture to obtain the stretch layer compound for later use.

[0024] B2. First, plasticize natural rubber, butadiene rubber, and chloroprene rubber for 80-120 seconds, then add zinc oxide, aromatic oil, vulcanizing agent, and sodium succinate sulfonate and continue mixing for 160-180 seconds, and then calender to obtain the compression layer rubber compound for later use.

[0025] B3, heating the stretching layer rubber prepared in step B1 to melt, then pulling the pretreated tempered brown wire from the molten stretching layer rubber to the stretching layer rubber to form a buffer cord, then winding it through the rotating roller to form a pre-use layer;

[0026] B4, bonding the compression layer rubber obtained in step B2 to the lower part of the pre-use layer to form a base layer, then wrapping the base layer through the wrapping layer to form a pre-use triangular belt, putting the pre-use triangular belt into the mold and sending it into the curing tank for vulcanization to obtain the triangular belt.

[0027] The present application has the following beneficial effects:

[0028] In the preparation process of the stretching layer, modified polyimide is introduced, and the introduction of modified carborane in the preparation process introduces large free volume benzene rings and trifluoromethyl groups in the polyimide main chain, which can increase the distance between molecular chains, limit the interaction and accumulation between chains, and the molecular chain is distorted to form a spatial asymmetric structure, reducing the crystallization tendency of polyimide, effectively improving the processing performance of polyimide and ensuring its thermal stability and mechanical properties; in addition, by pretreating the tempered brown wire, the adhesion between the skeleton and the rubber is increased, the overall performance is improved, and the service life is further prolonged. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0030] The natural rubber used in this invention was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; the styrene-butadiene rubber was purchased from Wuhan Xinyang Ruihe Chemical Technology Co., Ltd.; the aromatic oil was purchased from Chengdu Boruit Chemical Technology Co., Ltd.; zinc oxide CAS: 1314-13-2; stearic acid CAS: 57-11-4; sodium tripolyphosphate CAS: 7758-29-4; cis-butadiene rubber was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; chloroprene rubber was purchased from Wuhan Belka Biomedical Co., Ltd.; sodium succinate sulfonate... Purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; Bisphenol F epoxy resin purchased from Hubei Nuona Technology Co., Ltd.; Tempered brown fiber purchased from Weihai Tiancheng Hualun Special Belt Core Co., Ltd.; N,N-Dimethylacetamide CAS: 127-19-5; 4,4'-Diaminodiphenyl ether CAS: 101-80-4; 3,3',4,4'-Biphenyltetracarboxylic dianhydride CAS: 2420-87-3; Pyromellitic dianhydride CAS: 89-32-7; Xylene CAS: 1330-20- 7; Triethylamine CAS: 121-44-8; Acetone CAS: 116-09-6; Toluene CAS: 108-88-3; Decaborane CAS: 17702-41-9; 1,2-Bis(4-methoxyphenyl)acetylene CAS: 2132-62-9; Anhydrous dichloromethane CAS: 75-09-2; Boron tribromide CAS: 10294-33-4; 4-(trifluoromethyl)benzyl chloride CAS: 939-99-1; Benzyltriethylammonium chloride CAS: 56-37-1; Anhydrous sodium sulfate CAS: 15124-09-1; Dibutyl phthalate CAS: 84-74-2; Benzyl dimethylamine CAS: 539-48-0; Triethylenetetramine CAS: 112-24-3; Liquid nitrile rubber CAS: 25265-19-4; N,N-Dicyclohexyl-2-benzothiazole sulfenamide CAS: 4979-32-2; Tetrabenzylthiuram disulfide CAS: 10591-85-2; All reagents are commercially available.

[0031] Example 1

[0032] A high and low temperature resistant tempered coir filament triangular belt, the triangular belt includes a reinforcing layer, an extension layer above the reinforcing layer, a compression layer below the reinforcing layer, and a fabric covering layer wrapped around the outside of the extension layer and the compression layer.

[0033] The reinforcing layer is made of pre-treated tempered brown fibers.

[0034] The tensile layer comprises the following raw materials in parts by weight: 32 parts natural rubber, 45 parts styrene-butadiene rubber, 22 parts modified polyimide, 5 parts zinc oxide, 4 parts stearic acid, 7 parts aromatic oil, and 6 parts sodium tripolyphosphate.

[0035] The compression layer comprises the following raw materials by weight: natural rubber 24 parts, butadiene rubber 54 parts, chlorobutyl rubber 10 parts, zinc oxide 5 parts, aromatic oil 10 parts, vulcanizing agent 9 parts, sodium succinate sulfonate 4 parts; wherein the vulcanizing agent is a mixture of N,N-dicyclohexyl-2-benzothiazole sulfenamide and tetrabenzyl thiuram disulfide in a mass ratio of 1:1.

[0036] The preparation process of the modified polyimide is as follows: 55 parts by weight of N,N-dimethylacetamide is used as a solvent, 15 parts by weight of modified carborane is added, 35 parts by weight of 4,4'-diamino diphenyl ether is added after stirring, 35 parts by weight of 3,3',4,4'-biphenyl tetracarboxylic dianhydride and 25 parts by weight of pyromellitic dianhydride are added under ice bath conditions after the 4,4'-diamino diphenyl ether is completely dissolved, a viscous mixture is obtained after 5 hours of reaction, 25 parts by weight of dimethylbenzene is added and stirred uniformly, 16 parts by weight of triethylamine is added dropwise, stirring is uniform, the temperature is raised to 150 DEG C by heating, water is refluxed for 4 hours, and then powder is precipitated, the powder is filtered after cooling, washed in acetone, filtered, and dried, the drying conditions are 80 DEG C in a vacuum drying oven for 5 hours, then the temperature is raised according to the degree of temperature rise, and the temperature rise program is as follows: 1 hour at 100 DEG C and 150 DEG C, 2 hours at 200 DEG C and 250 DEG C, and the modified polyimide is obtained after cooling to room temperature.

[0037] The preparation process of the modified carborane is as follows:

[0038] S1, under a nitrogen atmosphere, 65 parts by weight of toluene and 18 parts by weight of decaborane are added to a reactor and stirring is started, then 20 parts by weight of acetonitrile is added, heating is refluxed for 3 hours, after cooling to room temperature, 20 parts by weight of 1,2-bis(4-methoxyphenyl)acetylene is added, heating is continued for 16 hours, after cooling, the solvent is removed under reduced pressure, and a white solid is obtained;

[0039] S2, under a nitrogen atmosphere, the white solid obtained in step S1 is added to a light-proof reactor with 24 parts by weight of anhydrous dichloromethane and cooled in ice water, 18 parts by weight of boron tribromide is slowly added, the reaction is carried out for 2 hours, the temperature is raised to room temperature and stirred for 20 hours to obtain a white solid powder;

[0040] S3, under a nitrogen atmosphere, the white solid powder obtained in step S2, 38 parts by weight of 4-(trifluoromethyl)benzyl chloride and 8 parts by weight of benzyltriethylammonium chloride are mixed and reacted at an elevated temperature for 3 hours, then 38 parts by weight of 20% (mass fraction) sodium hydroxide aqueous solution is added dropwise, after the addition is completed, the reaction is continued for 2 hours and then stopped, it is naturally cooled to room temperature and filtered, the filtrate is washed with water 4 times, anhydrous sodium sulfate is added and left overnight, the filtrate is filtered and dried to obtain a viscous liquid, and the modified carborane is obtained after drying, the drying conditions are 95 DEG C in a vacuum drying oven for 20 hours.

[0041] The pretreatment process of the tempered brown wire is as follows:

[0042] A1, 12 parts by weight of dibutyl phthalate, 15 parts by weight of benzene dimethylamine, 3 parts by weight of triethylene tetramine, 10 parts by weight of liquid butyl nitrile rubber, and 65 parts by weight of bisphenol F epoxy resin are mixed and stirred uniformly at 60°C, and then the temperature is increased to 80°C for 3h to obtain a viscous liquid, which is prepared for use;

[0043] A2, the tempered brown wire is placed in the viscous liquid obtained in step A1, the liquid is filled on the tempered brown wire, and then the tempered brown wire is placed in a heating container and treated at 200°C for 45min to obtain a pretreated tempered brown wire.

[0044] A method for preparing a high and low temperature resistant tempered brown wire triangular belt, comprising the following steps:

[0045] B1, the natural rubber, styrene butadiene rubber and modified polyimide are first plasticized for 100s, then zinc oxide, stearic acid, aromatic oil and sodium tripolyphosphate are added and mixed for 200s, and then calendering is performed to obtain an extension layer rubber compound, which is prepared for use;

[0046] B2, the natural rubber, cis-butadiene rubber and chloroprene rubber are first plasticized for 90s, then zinc oxide, aromatic oil, vulcanizing agent and sodium succinate sulfonate are added and mixed for 170s, and then calendering is performed to obtain a compression layer rubber compound, which is prepared for use;

[0047] B3, the extension layer rubber compound prepared in step B1 is heated to melt, then the pretreated tempered brown wire is pulled through the molten extension layer rubber compound to wrap the pretreated tempered brown wire to form a buffer cord, and then the buffer cord is wound through a rotating roller to form a pre-use layer;

[0048] B4, the compression layer rubber compound obtained in step B2 is bonded to the lower part of the pre-use layer to form a base layer, and then the base layer is wrapped by a wrapping layer to form a pre-use triangular belt, and the pre-use triangular belt is placed in a mold and sent into a vulcanization tank for vulcanization to obtain the triangular belt.

[0049] Example 2

[0050] Compared with example 1, the raw material ratio in the preparation of the triangular belt is different, and the process conditions in the preparation process are different, and the rest refers to example 1.

[0051] Specifically, the extension layer includes the following raw materials by weight: natural rubber 25 parts, styrene butadiene rubber 35 parts, modified polyimide 15 parts, zinc oxide 3 parts, stearic acid 2 parts, aromatic oil 5 parts, and sodium tripolyphosphate 2 parts;

[0052] The compression layer comprises the following raw materials by weight: natural rubber 20 parts, butadiene rubber 45 parts, chlorobutyl rubber 8 parts, zinc oxide 3 parts, aromatic oil 8 parts, vulcanizing agent 8 parts, sodium sulfonate succinate 3 parts;

[0053] In the preparation process of the modified polyimide, 3,3',4,4'-diphenyl tetracarboxylic dianhydride and pyromellitic dianhydride are added under ice bath condition and reacted for 4 h, then dimethylbenzene is stirred uniformly, triethylamine is added dropwise, stirring is uniform, the temperature is raised to 145 DEG C by heating, and water is refluxed out for 3 h before powdering; the powdery substance is washed in acetone, filtered and dried, and the drying condition is 75 DEG C in a vacuum drying oven for 4 h.

[0054] In the preparation process of the modified carborane, in step S1, acetonitrile is added and heated to reflux for 2 h, 1,2-bis(4-methoxyphenyl)acetylene is added, and heating to reflux is continued for 12 h; in step S2, boron tribromide is added and reacted for 1 h, the temperature is raised to room temperature, and stirring reaction is carried out for 18 h; in step S3, the white solid powder obtained in step S2, 4-(trifluoromethyl)benzyl chloride and benzyltriethylammonium chloride are mixed, the temperature is raised, and reaction is carried out for 2 h, sodium hydroxide is added dropwise, and reaction is continued for 1 h, the filtrate is washed with water for 3 times, and the drying condition is 85 DEG C in a vacuum drying oven for 16 h.

[0055] In the pretreatment process of the tempered brown silk, in step A1, the raw materials are mixed and stirred uniformly at 55 DEG C, and then the temperature is raised to 70 DEG C and reacted for 2 h; in step A2, the tempered brown silk is coated with the liquid, and then placed in a heated container and treated at 180 DEG C for 40 min.

[0056] In the preparation process of the high and low temperature resistant tempered brown silk triangular belt, in step B1, the natural rubber, styrene butadiene rubber and modified polyimide are first plasticated for 80 s, and then zinc oxide, stearic acid, aromatic oil and sodium tripolyphosphate are added and mixed for 180 s; in step B2, the natural rubber, butadiene rubber and chlorobutyl rubber are first plasticated for 80 s, and then zinc oxide, aromatic oil, vulcanizing agent and sodium sulfonate succinate are added and mixed for 160 s.

[0057] Example 3

[0058] Compared with example 1, the raw material ratio in the preparation of the triangular belt is different, the process conditions in the preparation process are different, and the rest is referred to example 1.

[0059] Specifically, the stretching layer comprises the following raw materials by weight: natural rubber 35 parts, styrene butadiene rubber 55 parts, modified polyimide 25 parts, zinc oxide 8 parts, stearic acid 6 parts, aromatic oil 12 parts, and sodium tripolyphosphate 8 parts.

[0060] The compression layer comprises the following raw materials in parts by weight: 30 parts natural rubber, 60 parts butadiene rubber, 12 parts chloroprene rubber, 9 parts zinc oxide, 12 parts aromatic oil, 12 parts vulcanizing agent, and 5 parts sodium succinate sulfonate.

[0061] In the preparation of modified polyimide, 3,3',4,4'-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride were added under ice bath conditions and reacted for 6 hours. Then, xylene was added and stirred evenly, followed by the dropwise addition of triethylamine and stirring. The mixture was heated to 155°C and refluxed for 5 hours to precipitate as powder. The powder was then washed in acetone, filtered, and dried in a vacuum drying oven at 85°C for 6 hours.

[0062] In the preparation of modified carborane, in step S1, acetonitrile was added and the mixture was heated under reflux for 5 h, then 1,2-bis(4-methoxyphenyl)acetylene was added and the mixture was heated under reflux for 18 h. In step S2, boron tribromide was added and the mixture was reacted for 2 h, then the temperature was raised to room temperature and stirred for 24 h. In step S3, the white solid powder obtained in step S2, 4-(trifluoromethyl)benzyl chloride and benzyltriethylammonium chloride were mixed and the temperature was raised for 4 h, sodium hydroxide was added dropwise and the mixture was reacted for 2 h. The filtrate was washed with water 5 times and dried in a vacuum drying oven at 100 °C for 24 h.

[0063] In the pretreatment process of tempered palm fibers, in step A1, the raw materials are mixed and stirred evenly at 65°C, and then the temperature is raised to 85°C for 4 hours; in step A2, the tempered palm fibers are coated with liquid and then placed in a heating container for treatment at 220°C for 60 minutes.

[0064] In the preparation process of high and low temperature resistant tempered coir filament V-belt, in step B1, natural rubber, styrene-butadiene rubber, and modified polyimide are first plasticized for 110s, and then zinc oxide, stearic acid, aromatic oil, and sodium tripolyphosphate are added and mixed for another 220s; in step B2, natural rubber, butadiene rubber, and chloroprene rubber are first plasticized for 120s, and then zinc oxide, aromatic oil, vulcanizing agent, and sodium succinate sulfonate are added and mixed for another 180s.

[0065] Comparative Example 1

[0066] Compared with Example 1, this comparative example does not perform pretreatment on the tempered brown filaments; all other aspects are the same as in Example 1. That is, the reinforcing layer is tempered brown filaments. In the process of preparing the high and low temperature resistant tempered brown filament V-belt, in step B3, the tension layer rubber compound is heated to melt, and then the tempered brown filaments are pulled from the molten tension layer rubber compound to form a buffer rope wrapped in the tension layer rubber compound. Then, it is wound up by a rotating roller to form a pre-use layer.

[0067] Comparative Example 2

[0068] The comparative example is not modified polyimide compared with example 1, and the rest is referred to example 1.

[0069] Specifically, the stretching layer comprises the following raw materials by weight: natural rubber 32 parts, styrene-butadiene rubber 45 parts, polyimide 22 parts, zinc oxide 5 parts, stearic acid 4 parts, aromatic oil 7 parts, and sodium tripolyphosphate 6 parts.

[0070] In the preparation process of the high and low temperature resistant tempered brown silk triangular belt, the natural rubber, styrene-butadiene rubber and polyimide are first plasticated for 80-110s in step B1, and then the zinc oxide, stearic acid, aromatic oil and sodium tripolyphosphate are added and mixed for 180-220s, and then the stretching layer compound is obtained by calendering.

[0071] Comparative example 3

[0072] The comparative example is not modified polyimide compared with example 1, and the rest is referred to example 1.

[0073] Specifically, the preparation process of the modified polyimide is as follows: 55 parts by weight of N,N-dimethylacetamide is used as a solvent, 15 parts by weight of carborane is added, after stirring, 35 parts by weight of 4,4'-oxydianiline is added, after the 4,4'-oxydianiline is completely dissolved, 35 parts by weight of 3,3',4,4'-diphenyltetracarboxylic dianhydride and 25 parts by weight of pyromellitic dianhydride are added under ice bath conditions, and the reaction is carried out for 5h to obtain a viscous mixture, 25 parts by weight of dimethylbenzene is added and stirred uniformly, then 16 parts by weight of triethylamine is added, after stirring, the temperature is increased to 150℃, water is refluxed for 4h, then the powder is precipitated, the temperature is lowered and filtered to obtain a powder, the powder is washed in acetone, filtered and dried, the drying conditions are 80℃ in a vacuum drying oven for 5h, then the temperature is increased according to the temperature increasing degree, and the temperature increasing program is as follows: constant temperature at 100℃ and 150℃ for 1h respectively, constant temperature at 200℃ and 250℃ for 2h respectively, and the modified polyimide is obtained after cooling to room temperature.

[0074] Comparative example 4

[0075] The comparative example is not modified polyimide compared with example 1, and the rest is referred to example 1.

[0076] Specifically, the stretching layer comprises the following raw materials by weight: natural rubber 32 parts, styrene-butadiene rubber 45 parts, polyimide 22 parts, zinc oxide 5 parts, stearic acid 4 parts, aromatic oil 7 parts, and sodium tripolyphosphate 6 parts.

[0077] In the preparation process of the high and low temperature resistant tempered brown wire triangular belt, the natural rubber and styrene-butadiene rubber are first plasticated for 80-110s in step B1, then zinc oxide, stearic acid, aromatic oil and sodium tripolyphosphate are added and mixed for 180-220s, and then calendering is performed to obtain the extension layer compound, which is ready for use.

[0078] Related tests:

[0079] Fatigue life test method:

[0080] The sample is cut to a length of 100mm, a width of 20mm and a thickness of 4mm, and then placed in a fatigue testing machine for testing. The initial test time A is recorded, and when the triangular belt shows abnormal phenomena such as cracks, the termination time B is recorded, and the fatigue life = B-A.

[0081] The tensile strength is tested by a triangular belt tensile strength tester.

[0082] The test results are shown in Table 1:

[0083] Table 1

[0084]

[0085] Related tests of the extension layer compound:

[0086] Tensile properties: GB / T 528-1998, hardness GB / T 6031-1998, DIN abrasion GB / T 9867-88, low temperature resistance: after being placed at -40℃ for 48h, whether cracks appear is observed. Thermal stability: the prepared sample is placed at 200℃ for 12h, and the appearance after heat treatment is observed. The test data are shown in Table 2.

[0087] Table 2

[0088]

[0089] The test results show that the fatigue life and tensile strength of the triangular belts prepared in Examples 1-3 are higher than those of Comparative Examples 1-4, and the test performance of Example 1 is the best. In the related performance test of the tensile layer compound, the tensile strength and hardness of Examples 1-3 are higher than those of Comparative Examples 1-4. In the wear performance test, the wear amount of Example 1 is the smallest. In the low temperature resistance test, no cracks are found in Examples 1-3 and Comparative Example 1, while slight cracks are found in Comparative Example 3, and obvious cracks are found in Comparative Examples 2 and 4. By observing the morphology after heat treatment, it is found that direct addition of polyimide (Comparative Example 2) and direct modification of polyimide with carborane (Comparative Example 3) after heat treatment all appear slight deformation, while no polyimide is added during preparation (Comparative Example 4) after heat treatment, which is deformed more seriously. The results show that the addition of modified polyimide in the tensile layer can effectively improve the mechanical properties, low temperature resistance and high temperature resistance of the material.

[0090] Compared with the prior art, the modified polyimide is introduced in the preparation process of the stretching layer, the polyimide molecular main chain contains a large number of imide rings and aromatic rings, and has a strong conjugation effect between the rings, the molecular chain has strong rigidity, and the intermolecular force is strong, so that the polyimide has excellent high-temperature resistance and excellent mechanical properties, but due to the electronic polarization and crystallinity in the aromatic rigid structure of the polyimide, there is a strong interaction between the polyimide molecules, causing the molecules to be tightly accumulated, and the processing performance is generally poor; the carborane is a large volume electron-deficient structure rich in B elements in a icosahedral cage, and has excellent high-temperature stability and chemical stability, so in the present application, the modified carborane is introduced to modify the polyimide to further improve the performance of the prepared product, that is, N,N-dimethylacetamide is used as a solvent, modified carborane is added, and under certain conditions, the modified carborane is reacted with 4,4'-diamino diphenyl ether, 3,3',4,4'-biphenyl tetracarboxylic dianhydride and pyromellitic dianhydride to obtain modified polyimide; wherein in the preparation process of the modified carborane, first, toluene, decaborane and acetonitrile are mixed and heated to reflux, then nucleophilic substitution reaction occurs with anhydrous dichloromethane and boron tribromide under an inert atmosphere, and finally, reaction occurs with 4-(trifluoromethyl) benzyl chloride under the catalysis of benzyl triethyl ammonium chloride, and further, an aqueous sodium hydroxide solution is added dropwise, to obtain the modified carborane; the modified carborane has a benzene ring and a trifluoromethyl group introduced thereon, and in the process of preparing the modified polyimide by using the modified carborane, a large free volume side group (benzene ring, trifluoromethyl group) is introduced into the polyimide main chain, which can increase the distance between the molecular chains, limit the interaction and accumulation between the chains, the molecular chain is distorted to form a spatial asymmetric structure, and the crystallization tendency of the polyimide is reduced, but the rigidity of the chain is not damaged, the processing performance of the polyimide can be effectively improved, and the thermal stability and mechanical properties are ensured. In addition, the tempered brown silk is pretreated in the present application: dibutyl phthalate, benzylamine, triethylenetetramine, liquid nitrile rubber and bisphenol F epoxy resin are used to prepare a viscous liquid, the tempered brown silk is placed in the viscous liquid and heated to obtain pretreated tempered brown silk, and the pretreated tempered brown silk can increase the adhesion between the skeleton and the rubber, improve the overall performance, and further prolong the service life.

[0091] It is to be understood that the terminology used herein such as first and second, and the like, is only used to distinguish one entity or action from another entity or action, and does not necessarily require or imply any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0092] While embodiments of the present application have been shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application. The scope of the application is thus defined by the appended claims and their equivalents.

Claims

1. A high and low temperature resistant tempered brown silk triangular belt comprising a strength layer, characterized in that, The upper part of the strong layer is provided with a stretching layer, and the lower part of the strong layer is provided with a compression layer, and the outer side of the stretching layer and the compression layer is wrapped with a cloth layer; The strong layer is a pretreated tempered brown silk; The stretching layer comprises the following raw materials in weight parts: natural rubber 25-35 parts, styrene-butadiene rubber 35-55 parts, modified polyimide 15-25 parts, zinc oxide 3-8 parts, stearic acid 2-6 parts, aromatic oil 5-12 parts, and sodium tripolyphosphate 2-8 parts; The compression layer comprises the following raw materials in weight parts: natural rubber 20-30 parts, cis-butadiene rubber 45-60 parts, chlorobutadiene rubber 8-12 parts, zinc oxide 3-9 parts, aromatic oil 8-12 parts, vulcanizing agent 8-12 parts, and sodium succinate sulfonate 3-5 parts; The preparation process of the modified polyimide is as follows: N,N-dimethylacetamide is used as a solvent, modified carborane is added, 4,4'-diamino diphenyl ether is added after stirring, 3,3',4,4'-biphenyl tetracarboxylic dianhydride and pyromellitic dianhydride are added under ice bath conditions after the complete dissolution of 4,4'-diamino diphenyl ether, a viscous mixture is obtained after 4-6 h of reaction, dimethylbenzene is added after stirring, triethylamine is added dropwise, stirring is uniform, the temperature is increased to 145-155 DEG C by heating, water is refluxed out for 3-5 h, and then the powder is precipitated, the powder is filtered after cooling, the powder is washed in acetone, filtered, and dried, then the temperature is increased according to the temperature increase program, the modified polyimide is obtained after cooling to room temperature.

2. The high and low temperature resistant tempered brown silk triangular belt according to claim 1, characterized in that, The preparation process of the modified carborane is as follows: S1, under an inert atmosphere, toluene and decaborane are added to a reactor and stirring is started, then acetonitrile is added, heating is refluxed for 2-5 h, 1,2-bis(4-methoxyphenyl)acetylene is added after cooling to room temperature, heating is continued to reflux for 12-18 h, the solvent is removed under reduced pressure after cooling, and a white solid is obtained; S2, under an inert atmosphere, the white solid obtained in step S1 is added to a light-proof reactor with anhydrous dichloromethane and cooled in ice water, boron tribromide is slowly added, reaction is carried out for 1-2 h, the temperature is increased to room temperature for stirring reaction for 18-24 h, and a white solid powder is obtained; S3, under an inert atmosphere, the white solid powder obtained in step S2, 4-(trifluoromethyl)benzyl chloride, and benzyltriethylammonium chloride are mixed and reacted for 2-4 h, then sodium hydroxide aqueous solution is added dropwise, the reaction is continued for 1-2 h after the completion of dropwise addition, and then the reaction is stopped, the mixture is naturally cooled to room temperature and filtered, the filtrate is washed with water, anhydrous sodium sulfate is added, the mixture is left overnight, the mixture is filtered and dried, and the modified carborane is obtained after drying.

3. The high and low temperature resistant tempered brown silk triangular belt according to claim 1, characterized in that, The pretreatment process of the tempered brown silk is as follows: A1, dibutyl phthalate, benzylamine, triethylenetetramine, liquid butanenitrile rubber, and bisphenol F epoxy resin are mixed and stirred uniformly at 55-65 DEG C, the temperature is increased to 70-85 DEG C, a viscous liquid is obtained after 2-4 h of reaction, and the liquid is reserved; A2, the tempered brown silk is placed in the viscous liquid obtained in step A1, the liquid is coated on the tempered brown silk, the tempered brown silk is placed in a heating container, and the tempered brown silk is treated at 180-220 DEG C for 40-60 min, and the pretreated tempered brown silk is obtained.

4. The high and low temperature resistant tempered brown silk triangular belt according to claim 1, characterized in that, The vulcanizing agent is a mixture of N,N-dicyclohexyl-2-benzothiazolesulfenamide and tetrabenzylthiuram disulfide in a mass ratio of 1:

1.

5. The high and low temperature resistant tempered brown silk triangular belt according to claim 1, characterized in that, The temperature rising procedure in the preparation of the modified polyimide is: constant temperature at 100 DEG C and 150 DEG C for 1 h each, constant temperature at 200 DEG C and 250 DEG C for 2 h each.

6. The high and low temperature resistant tempered brown silk triangular belt according to claim 2, characterized in that, The inert atmosphere is nitrogen or argon.

7. The high and low temperature resistant tempered brown silk triangular belt according to claim 2, characterized in that, The filtrate is washed with water for 3-5 times in step S3; the drying condition is drying in a vacuum drying oven at 85-100 DEG C for 16-24 h.

8. The method of claim 1-7, wherein the method is characterized in that, The method comprises the following steps: B1, the natural rubber, styrene butadiene rubber, modified polyimide is first plasticized, then zinc oxide, stearic acid, aromatic oil, sodium tripolyphosphate is added and mixed, then calendering is carried out to obtain the extension layer compound, which is ready for use; B2, the natural rubber, butadiene rubber, neoprene is first plasticized, then zinc oxide, aromatic oil, vulcanizing agent, sodium succinate sulfonate is added and mixed, then calendering is carried out to obtain the compression layer compound, which is ready for use; B3, the extension layer compound prepared in step B1 is heated to melt, then the pretreated tempered brown silk is pulled through the molten extension layer compound to wrap the pretreated tempered brown silk to form a buffer rope, then the buffer rope is wound through the rotating roller to form a pre-use layer; B4, the compression layer compound obtained in step B2 is bonded to the lower part of the pre-use layer to form a base layer, then the base layer is wrapped by a wrapping layer to form a pre-use triangular belt, the pre-use triangular belt is put into a mold and sent into a vulcanization tank for vulcanization to obtain the triangular belt.

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